STAMFORD, Conn. — Connecticut officials say a Christmas morning fire that killed a couple and three of their grandchildren was caused by old fireplace embers.

Officials say the fire in Stamford was an accident caused by hot fireplace embers that were discarded near a first-floor mudroom.

The officials say it isn't clear if the home had working smoke detectors.

Stamford Mayor Michael Pavia calls it a tragic accident.

Neighbors say they were awakened by screams shortly before 5 a.m. and rushed outside to help but could do nothing as flames devoured the large home.

The fire killed Lomer and Pauline Johnson, who were visiting their daughter Madonna Badger for the holidays. Badger's three daughters — 10-year-old Lily and 7-year-old twins Grace and Sarah — also died.

Badger and her male acquaintance escaped.